Polishing-bob.



No. 640,590. Patented Jan. 2,1900.

.1. mes & H. HART.

POLISHING 808.

(Application filed m 12, 1899.)

9 Fig. 2'.

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m: NORRIS PETERS cu. Pnuroumo" WASHHIGTON a c UNITED STATES PATENT OFFICE.

JOSEPH RIGG, OF YARDLEY, AND HENRY HART, OF HARBORNE, ENGLAND.

POLISHING-BOB.

SPECIFICATION forming part of Letters Patent No. 640,590, dated January 2, 1900. Application filed May 12,1899. Serial No. 716,600. (No model.)

To all whom, it may concern:

Be it known that we, JOSEPH RIGG, residing at Church Place, Yardley, in the county of Worcester, and HENRY HART, residing at 32 Regents road, Harborne, in the county of Warwick, England, subjects ofthe Queen of Great Britain, have invented certain new and useful Improvements in Polishing-Bobs of Leather, of which the following is a specification.

This invention has reference to polishing bobs of leather, such as are used for polishing metals, glass, and similar substances and and are formed of thick hides, such as walrushide, bufialo-hide, and bulls neck.

The objects of the invention are, first, the production of a bob of greater breadth (practically unlimited) than hitherto; secondly, to utilize scrap or waste parts of hides in the formation of the bobs, as well as the best portions thereof, and, thirdly, to reduce their cost of production and increase their wear. Usually such bobs are formed from full-sized solid leather pieces cut from the best and most suitable parts of hides, these pieces being turned circular in a machine. In this case there is considerable waste of material, especially having regard to hides, such as walrus, which have particular properties and thicknesses, which are rare, and which are not of equal thicknesses at all parts or flat enough or sufficiently within shape to form a true bob.

According to this invention, a bob of leather is made of any size and thickness from a congregation of small lumps, pieces, or cuttings or from granulated powder of the hide preferred by thoroughly mixing the said cuttings, lumps, or powder with a liquid or partly-liquid cement, working the same until it becomes a saturated adhesive mass of the proper pitch of dryness, and then submitting it in quantities to pressure in a mold of the size and shape of the bob required, which presses the whole of the cuttings together, so as to form when dry a hard consolidated inseparable mass having the desired qualities of a polishing-bob. During the application of the pressure as aforesaid the superfluous cement is squeezed out of the mass under treatment, so that when finished the bob is fairly dry.

An important feature of this invention is the composition of the cement used, as, while it must be efiective in the consolidation of the cuttings in the mass, it must not allow of the said molded mass drying harsh.

size or is ground to a coarse powder or granulated and is placed in quantities required in water, so as tobecome soaked or saturated, the said lumps or pieces swelling slightly and becomingsoftthereby. After atimethemass is taken from the water and thoroughly mixed with a liquid cement composed of water, glue, resin, gum-dragon, vinegar, and gutta-percha dissolved in carbon bisulfid, which finds its way into the pores of the leather lumps un til they become thoroughly saturated with it, the said mixing being continued until such time as the mass has been worked to the proper consistency and pitch of dryness. Portions of the mass are now taken and submitted to pressure in molds of the exact size (or approximately so) and shape of the bobs to be produced, the whole of the leather pieces or lumps being pressed and bound together and amalgamated through the said pressure and cement, so as to form hard set consolidated inseparable ma-sses having the desired qualities and the exterior shape of polishingbobs.

A mold wherein the mass is pressed together is shown in Figure 1 of the accompanying drawings, a bob a, constructed according to this invention, being shown in posi-' tion within the said mold. This mold is simply a metal ring 0, resting upon a suitable base 0 and its inner walls and also the face of the base are suitably greased before the mass is placed therein and thereon, so that the bob can be knocked out fairly easy. In this sheet of drawings a finished bob is also shown in edge view in Fig. 2 and in side View in Fig. 3, it having upon its sides in these figures thin leather disks d, which are ce-' mented thereon subsequent to the bob being molded. V

The cement used in the amalgamation has by experiment been found to be particularly effective when the materials forming it have the following proportions: water, one pint; glue, two ounces; resin, one-half ounce; gum dragon, one ounce; vinegar, one-fourth pint, and one and one-half ounces of gutta-percha, (this last named and the resin being dissolved by the carbon sulfid,) and in this cement the vinegar is a very important substance, as it keeps the leather from drying harsh in the consolidation.

The bobs after they leave the molds require to be further dried, and this may be done by a very slow heat in an oven of some kind or by being left to stand a considerable time.

In the drawings the bob a is solid-that is to say, it is formed entirely of amalgamated leather pieces; but it is obvious that it may be molded around a wooden core or on a mounting, especially in bobs of large diameter. It will at once be seen that by this invention there is practically no limit as to the thickness of a bob, as would be in the case of a hide such as walrus, and this is of great importance to the metal trades; further, that by constructing bobs according to this invention the frequent dressing necessary in leathercovered wooden bobs of ordinary construction is obviated.

The lumps, pieces, or cuttings from which the bobs according to this invention are formed need not be of any particular shape or size, so long as they are smallsay about half an inchas in their congregation and consolidation they are forced together irregular or without any arrangement.

Having now described our invention, what we claim, and desire to secure by Letters Patent, isi As a new article of manufacture, a polishing-bob consisting of leather cuttings or granulations amalgamated with water, glue, resin, gum-dragon, vinegar, gutta-percha and carbon bisulfid, substantially as described.

JOSEPH RIGG. HENRY HART.

Witnesses:

ALBERT NEWEY, A. F. RIDDLE. 

